Further Studies on Temperature Dependences of Isotope Effects

摘要: It is shown that, although the temperature behavior calculated in harmonic approximation for a specific isotope‐exchange reaction may be extremely sensitive to force fields used computations, small force‐field changes do not affect significantly over‐all prevalence of temperature‐dependence “anomalies.” In series calculations large number 13C‐, 18O‐, and D‐isotope‐exchange equilibria involving organic inorganic molecules, such “anomalies” are found 50 171 13C exchanges considered, 84 153 18O 40 120 D considered. When present results combined with previous 15N‐ 18O‐exchange reactions simple appear about 40% almost 700 investigated. concluded that isotope‐effect due unusual or fortuitous combinations constants, but represent more general phenomenon. Further, ...